Systems and Methods for Needle Access to an Intervertebral Disc

ABSTRACT

A catheter with a balloon anchor may be sized to fit through an inner needle and introduced into the patient through the needle. The inner needle may comprise an atraumatic needle with a side port and/or a blunt tip. The catheter may include a radiopaque coil disposed over the distal portion of the catheter body to assist with catheter placement when viewed with fluoroscopy and/or x-ray. The distal portion of the catheter can be very flexible. A balloon inflation tube may terminate proximal to a proximal end of the expandable balloon anchor such that the distal portion of catheter can be flexible. This termination of the inflation tube may also position the inflation tube away from the annulus and nerve roots, so as to avoid irritation of the annulus and rubbing of the nerve roots that may potentially obscure FAD test results.

CROSS-REFERENCES TO RELATED APPLICATIONS

The subject matter of the present application is related to but does notclaim the benefit of the following commonly assigned and concurrentlyfiled U.S. patent applications Ser. No. ______ filed on Jun. 15, 2007,entitled “DEVICE AND METHODS FOR INTRODUCING A CATHETER INTO ANINTERVERTEBRAL DISC”(attorney docket no. 019433-001900US); ______ filedon Jun. 15, 2007, entitled “SYSTEMS AND METHODS FOR NEEDLE ACCESS TOINTERVERTEBRAL DISC”(attorney docket no. 019433-002410US); and ______filed on Jun. 15, 2007, entitled “SYSTEMS AND METHODS FOR NEEDLE ACCESSTO INTERVERTEBRAL DISC”(attorney docket no. 019433-002420US), the fulldisclosures of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention generally relates to medical devices and methods.More particularly, the present invention relates to devices and methodsfor diagnosing and/or treating spinal pain.

Back pain takes an enormous toll on the health and productivity ofpeople around the world. According to the American Academy of OrthopedicSurgeons, approximately 80 percent of Americans will experience backpain at some time in their life. In just the year 2000, approximately 26million visits were made to physicians' offices due to back problems inthe United States.

In at least some instances, surgical prostheses can be used to relieveback pain. Many of these prosthesis relieve pressure and/or irritationof nerve roots near the vertebral joints. Such treatments can beeffective when the source of pain can be localized to a specificinter-vertebral joint and/or disc.

Unfortunately, back pain can be difficult and invasive to accuratelydiagnose in an effective manner that determines where the painoriginates. Axial pain can be caused by disc failure that results incompression of nerves. “Discogenic pain,” for example, is a type ofspinal pain originating in one or more intervertebral discs (soft tissuestructures between vertebrae of the spine). The physical examination andcomplaints of the patient may merely provide general clues as to thecause and general location of the pain.

One approach to determine the source of back pain, can be to performprovocative discography. This procedure can include penetrating thepatient's skin and injecting a contrast agent into the disc. The disccan be imaged with fluoroscopy, radiographs, CT scans, or the like withthe aid of the contrast agent. Alternatively, a new technique referredto as Functional Anesthetic Discography (FAD) has been developed whereinthe disc can be further evaluated with functional tests in which thepatient assumes a painful position and the disc is injected with ananalgesic or similar substance to determine if the pain diminishes inresponse to the injection into the disc.

Placement of the spinal needles to test the discs may require skill andtime on the clinician's part and can be painful to the patient, evenwhen good technique is used. In some instances, provocative discographymay use two needles for each disc. As the patient may have more that onedisc that may be a possible source of back pain, each of these suspecteddiscs may be tested to determine which, if any, of the discs is thesource of the patient's pain. The testing of multiple discs, for examplethree discs, can be time consuming and may result in multiple injectionsfor the patient, each of which can be painful. Invasive tearing oftissues, for example associated with conventional needles and the like,may cause tissue trauma and delay recovery in some patients. Inaddition, some catheters and needles may potentially rub against nerveroots, such that the patient experiences pain, and in some instances mayobscure test results.

For these reasons, it would be desirable to provide apparatus andmethods for facilitating the diagnosis and treatment of spinal pain. Itwould be particularly desirable if such methods and apparatus were lessinvasive and painful than current methods and apparatus, and assuredreliable determination of the source of patient pain, ideally whileallowing the clinician flexibility with respect to which approach isused in a manner that accommodates patient variability.

Related devices and methods are disclosed in U.S. Patent Publication No.2005/0234425 describes a Functional Anesthetic Discography (FAD)catheter, the full disclosure of which is incorporated herein byreference. Additional art that may be relevant includes U.S. applicationSer. No. 11/021,786 and 60/826,472, the full disclosures of which areincorporated herein by reference, and International Publication No. WO2005/102440.

SUMMARY OF THE INVENTION

Embodiments of the present invention may provide less invasive and safersystems and methods to access, diagnose, and treat spinal pain. Acatheter, such as an FAD catheter with a balloon anchor, may be sized tofit through a relatively small inner needle, for example a 0.9 mm orsmaller needle. Optionally, the clinician may use a needle that hasalready been placed, thereby benefiting from a pre-existing access portand decreasing the invasiveness of the procedure. In specificembodiments, an atraumatic needle can be used to introduce the catheterinto the interior of the disc of the patient. Such atraumatic needlesmay reduce the incidence of complications and trauma to the penetratedtissue, for example leakage through a penetrated disc annulus, orimpaired healing from the trauma imparted on the annulus by passing theneedles. The atraumatic needle may comprise a side port and blunt tip tominimize tissue damage. The tip will usually comprise an integratedsharpened end, but could alternatively comprise a radiofrequencyelectrode (capable of applying cutting current), a removably orseparately formed sharpened end, or the like. The catheter may include aradiopaque marker, for example a coil, disposed over the distal portionof the catheter body to assist with catheter placement when viewed withfluoroscopy and/or x-ray. In addition to making the catheter visiblewith fluoroscopy and/or x-ray, the coil may be very flexible, such thatthe distal portion of the catheter can be very flexible. The coil alongthe distal portion of the catheter may provide improved safety, as thecoil may retain the distal catheter portion in the unlikely, yetpotentially serious, situation in which the distal tip of the catheterbreaks. In some embodiments, an inflation tube may terminate proximal toa proximal end of the expandable balloon anchor. This termination of theinflation tube, along with the flexible coil, may permit the distalportion of catheter to be flexible. This termination of the inflationtube may also position the inflation tube away from the annulus andnerve roots, so as to avoid irritation of the annulus and rubbing of thenerve roots that may potentially obscure FAD test results.

In a first aspect, embodiments of the present invention provide a methodfor positioning a catheter in an interior of an intervertebral disc. Themethod comprises percutaneously advancing a first needle through a skintoward the intervertebral disc. A second needle may be advanced througha lumen of the first needle to penetrate through a surface of theintervertebral disc into the interior of the disc. A catheter may beadvanced through a lumen of the second needle into the interior of thedisc.

In many embodiments, the first needle may be advanced with a stylet orobturator in its lumen, the stylet or obturator may be removed after thefirst needle has reached the surface location. The first needle may havean inner diameter of no more than 1.7 mm and a length in the range from3 cm to 26 cm.

In some embodiments, the second needle can be advanced with a stylet orobturator in its lumen, the stylet or obturator can be removed after thesecond needle has reached the interior of the disc. The second needlemay have an outer diameter no greater than 1.5 mm and an inner diameterof at least 0.38 mm. The catheter may have an outside cross sectionalsize no greater than 1.5 mm and a length in the range from 30 cm to 62cm.

In many embodiments indicia on a proximal portion of the catheter may beobserved as the catheter is advanced through the lumen of the secondneedle. The indicia may indicate a position of the catheter relative toa distal end of the second needle so that a user will know when thecatheter has passed from the second needle into the interior of thedisc. The indicia may comprise a scale formed on the exterior of aproximal portion of the catheter. In specific embodiments, the indiciamay comprise a color change on the catheter.

In some embodiments, the catheter can be advanced through a side port ofthe second needle to advance the catheter into the interior of the disc.The catheter may be advanced into the interior of the disc through theside port at a deflection angle of about 5 to 35 degrees from the secondneedle. The second needle can be retracted such that the catheter slidesalong a side port of the second needle and a distal tip of the catheterremains in the interior of the disc. In specific embodiments, the firstneedle can be retracted to retract the second needle and slide the sideport along the catheter.

In some embodiments, an expandable balloon can be inflated to anchor thecatheter in the disc interior after the second needle has beenretracted.

In another aspect, embodiments of the present invention provide a systemfor positioning a catheter in an intervertebral disc of a patient inwhich the intervertebral disc has an annulus and a nucleus. The systemcomprises a needle sized to extend through a skin of the patient andthrough the annulus into the nucleus. The needle comprises an innerlumen and a closed distal tip. The system also comprises a cathetersized to fit inside the lumen of the needle and extend into the nucleus.

In some embodiments, the catheter comprises a balloon anchor sized topass through the lumen into the nucleus.

In many embodiments, the distal tip of the needle comprises a taperedprofile, and the distal tip of the needle may comprise an atraumaticneedle tip. For example, the closed distal tip of the needle maycomprise a side port, and the lumen may extend to the side port. Theneedle may be adapted to slide along the catheter and out the side portwhile the atraumatic needle tip is withdrawn through the annulus. Thus,the catheter can remain in the nucleus after the atraumatic needle hasbeen withdrawn.

In some embodiments, the system comprises an outer needle to penetrate askin of the patient. The outer needle may comprise a lumen, and theneedle can be sized to fit inside the lumen of outer needle.

In some embodiments, the catheter comprises a bend radius from about 5to 15 mm. The side port can be adapted to pass the catheter with thebend radius from about 5 to 15 mm so as to slide the catheter throughthe side port while the needle is retracted through the annulus.

In specific embodiments, the atraumatic needle tip comprises a SpecialSprotte needle tip, and the needle comprises an outside diameter no morethan about 0.92 mm.

In many embodiments, the catheter comprises a balloon anchor sized topass through the side port.

In some embodiments, the system comprises an adapter that connects to alumen of the catheter, and a wing nut to tighten the adapter on thecatheter lumen. The wing nut may comprise a slot sized to pass the lumenwhen the wing nut is removed from the adapter.

In another aspect, embodiments of the present invention provide a methodof positioning a catheter in an intervertebral disc of a patient inwhich the intervertebral disc has an annulus and a nucleus. The methodcomprises advancing a needle to penetrate through a surface of theintervertebral disc into the interior of the disc. A catheter isadvanced through a lumen of the needle into the interior of the disc.

In many embodiments, a balloon is inflated to anchor the catheter in thedisc.

In another aspect, embodiments of the present invention provide a systemfor positioning a catheter in an interior of an intervertebral disc. Thesystem may comprise a first needle capable of receiving a firstremovable stylet for establishing a percutaneous path through a skintowards the intervertebral disc in a patient's body. The system may alsocomprise a second needle that is capable of receiving a second removablestylet. The second needle can be sized to advance through a lumen of thefirst needle, after the first removable stylet has been removed. Thesecond needle can be advanced into the interior of the intervertebraldisc. The system may further comprise a catheter that is sized forintroduction through a lumen of the second needle after the secondstylet has been withdrawn.

In many embodiments, the first needle may include a removable stylet,obturator or trocar to inhibit coring. The first needle may have aninner diameter of no more than 1.7 mm and a length in the range from 3cm to 20 cm. The second needle may include a removable stylet orobturator to inhibit coring. In specific embodiments, the second needlemay have an outer diameter no greater than 1.5 mm, an inner diameter ofat least 0.38 mm, and a length in a range from 10 cm to 30 cm. Thecatheter may have an outside cross sectional size no greater than 1.5 mmand a length in the range from 30 cm to 62 cm.

In some embodiments, the catheter may comprise indicia over a proximalportion thereof. The indicia may indicate the position of the distal endof the catheter relative to the distal end of the second needle. Theindicia may comprise a scale formed printed or etched on a surface ofthe catheter. In specific embodiments, the indicia may comprise a colorchange on the catheter.

In many embodiments, the second needle may comprise an atraumatic needleadapted to minimize tissue damage with at least one of an atraumatic tipor a side port. The second needle comprises a ramp near the side port topass the catheter through the side port at a deflection angle of about 5to 35 degrees from the second needle. In specific embodiments, thesecond needle may comprise a Sprotte needle. The side port may becapable of sliding along the catheter such that the catheter remainsnear the disc when the second needle is retracted. The catheter maycomprise an expandable balloon sized to pass through the side port.

In specific embodiments, at least one of the first needle or the secondneedle, or a component of one of the needles, may comprise tungsten,rhenium, molybdenum, tantalum, palladium, cobalt-chromium,tungsten-rhenium, tungsten-carbide or molybdenum-rhenium.

In a further aspect, embodiments of the present invention provide acatheter for accessing an intervertebral disc. The catheter may comprisean elongate flexible catheter body having a proximal portion, a distalportion, and at least one lumen for introducing substances. The cathetermay also comprise an inflatable anchoring balloon on the distal portionof the catheter body. A radiopaque coil may be disposed over or throughat least a part of the distal portion of the elongate flexible catheterbody.

In many embodiments, an injection tube may extend from the proximalportion to or near a distal tip of the catheter body. An inflation tubemay extend from the proximal portion to or near the distal portion ofthe catheter body. The radiopaque coil can be disposed over a distalportion of the injection tube that passes through the inflatableanchoring balloon. The radiopaque coil may extend from a distal tip ofthe injection tube to a proximal portion of the catheter body.

In some embodiments, the catheter body may comprise a polymeric tubehaving a central passage which receives the inflation tube and theinjection tube. The inflation tube may comprise a metal tube, and theinjection tube may comprise a metal tube.

In specific embodiments, the catheter body may have an outside diametercapable of passing through a lumen of a 0.9 mm needle.

In another aspect, embodiments of the present invention may provide acatheter for accessing an intervertebral disc. The catheter may comprisean elongate flexible catheter body having a proximal portion, a distalportion, and at least one lumen for introducing substances. The cathetermay also comprise an inflation tube in the elongate body, and ananchoring balloon comprising an inflatable portion disposed on thedistal portion of the catheter body. The inflation tube may have adistal end, which terminates proximal to the inflatable portion of theballoon.

In specific embodiments, the distal end of the inflation tube may lieabout 5.5 mm proximally of a distal tip of the catheter body.

In many embodiments, the catheter may comprise an injection tube in theelongate body that extends distally past the distal end of the inflationtube and terminate near a distal tip of the catheter body. The injectiontube may extend distally beyond a distal end of the anchoring balloon bya distance of at least 2 mm. The portion of the catheter body distal tothe distal end of the inflation tube may be more flexible than theportion proximal to the distal end.

In some embodiments, the catheter body may comprise a polymeric tubethat has a central passage which receives the inflation tube and theinjection tube. The inflation tube may comprise a metal tube, and theinjection tube may comprise a metal tube.

In specific embodiments, the catheter body may be configured to passthrough the lumen of a 0.9 mm needle.

In specific embodiments, at least one of the coil, the injection tube orthe inflation tube comprises comprise tungsten, rhenium, molybdenum,tantalum, palladium, cobalt-chromium, tungsten-rhenium, tungsten-carbideor molybdenum-rhenium.

In another aspect, embodiments of the present invention may provide acatheter for accessing an intervertebral disc. The catheter may comprisean elongate flexible catheter body having a proximal portion, a distalportion, and at least one lumen. The catheter may also comprise aninflatable anchoring balloon on the distal portion of the catheter body,and an injection tube may extend through the at least one lumen from theproximal portion to a distal tip of the catheter body. An inflation tubemay extend through the at least one lumen from the proximal portion tothe distal portion of the catheter body. At least one of the inflationtube and the injection tube may be coated and/or treated over at least apart of the proximal portion to inhibit fatigue fracturing.

In many embodiments, the at least one tube of the catheter may be coatedwith a polymer. The polymer may comprise at least one of poly(aryl etherketone), polyethylene terephthalate, polyetherimide, nylon, a filled orribbed blend, or a combination thereof.

In some embodiments, the at least one tube may be composed of a metaland annealed to improve metal fatigue characteristics. Both theinflation tube and the injection tube can be coated and/or treated toinhibit fatigue fracturing.

In many embodiments, the catheter body may comprise a polymeric tubehaving a central passage which receives the inflation tube and theinjection tube. The catheter body may be reinforced with a metal orpolymer.

In specific embodiments, the catheter body may an outside diametercapable of passing through a lumen of a 0.9 mm needle.

In another aspect, embodiments of the invention provide a catheter foraccessing an intervertebral disc. The catheter comprises an elongateflexible catheter body having a proximal portion, a distal portion, andat least one lumen for introducing substances. The catheter may alsocomprise an inflatable anchoring balloon on the distal portion of thecatheter body. An injection tube may extend from the proximal portion toa distal tip of the catheter body, and an inflation tube may extend fromthe proximal portion to the distal portion of the catheter body. Atleast one of the injection tube and the inflation tube may be marked foridentification, for example to allow the clinician to distinguish easilyamong the tubes.

In many embodiments, the at least one tube is marked with a color. Theat least one tube may have a terminal connector which is marked. Forexample, the terminal connector may be marked with a color.

The catheter body may comprise a polymeric tube having a central passagewhich receives the inflation tube and the injection tube. The inflationtube may comprise a metal tube, and the injection tube may comprise ametal tube. In specific embodiments, the catheter body may have anoutside diameter capable of passing through a lumen of a 0.9 mm needle.

In many embodiments a system comprises the catheter for accessing theintervertebral disc as described above. The system may also comprise aballoon inflation source. The balloon inflation source may have aconnector which is marked similarly to the inflation tube. The systemmay also comprise an injection source, and the injection source may havea connector which is marked similarly to the injection tube.

In another aspect, embodiments of the present invention provide acatheter for accessing an intervertebral disc. The catheter may comprisean elongate flexible catheter body that has a proximal portion, a distalportion, and at least one lumen for introducing substances. The cathetermay also comprise an inflatable anchoring balloon on the distal portionof the catheter body. An inflation tube or lumen may have an inlet andan outlet and defining an inflation path. The outlet can be connected todeliver an inflation medium via the inflation path under pressure to theballoon. A pressure-relief structure can be connected or connectable inthe balloon inflation path to vent the inflation medium if the pressureexceeds a predetermined amount, such that over inflation and rupture ofthe balloon can be prevented.

In many embodiments, the catheter may comprise an isolation valve in theinflation tube or lumen so that the balloon inflation path can be closedafter the balloon is inflated. In some embodiments, the pressure reliefstructure may be positioned upstream of the isolation valve so thatpressure can vent while the inflation medium is being delivered but notafter the isolation valve is closed. In additional embodiments, thepressure relief structure may be downstream of the isolation valve sothat pressure can vent even after the valve is closed.

In some embodiments, the pressure relief structure may comprise a partof the isolation valve, and the pressure relief structure and theisolation valve may be parts of an inflation syringe.

In many embodiments, the catheter body may comprise a polymeric tubehaving a central passage which receives the inflation tube and aninjection tube. The inflation tube may comprise a metal tube, and theinjection tube may comprise a metal tube. In specific embodiments, thecatheter body may have an outside diameter capable of passing throughthe lumen of a 0.9 mm needle. In some embodiments, the predeterminedamount may comprise a range from about 680 kPa to about 1620 kPa.

In another aspect, embodiments of the present invention provide acatheter for accessing an intervertebral disc. The catheter may comprisean elongate flexible catheter body having a proximal portion, a distalportion, and at least one lumen for introducing substances. The cathetermay also comprise an inflatable anchoring balloon on the distal portionof the catheter body. An injection tube may extend from the proximalportion to a distal tip of the catheter body. An inflation tube mayextend from the proximal portion to the distal portion of the catheterbody. A one-way valve may be attached to at least one of the injectiontube or the inflation tube, such that the one-way valve may avoid thebackflow of substances through the catheter, for example duringinflation or injection at high pressure. The one-way valve may also helpto retain pressure in the balloon and make it easier for the clinicianto close the stopcock valve.

In many embodiments, the one-way valve may be attached to the inflationtube to hold pressure after the balloon has been inflated. The one-wayvalve can be attached to the injection tube to inhibit leakage ofsubstances after they have been injected. The catheter body may comprisea polymeric tube having a central passage which receives the inflationtube and the injection tube. The inflation tube may comprise a metaltube, and the injection tube may comprise a metal tube. In someembodiments, at least one of the injection tube or the inflation tubecomprises tungsten, rhenium, molybdenum, tantalum, palladium,cobalt-chromium, tungsten-rhenium, tungsten-carbide ormolybdenum-rhenium. In specific embodiments, the catheter body may havean outside cross sectional size capable of passing through the lumen ofa 0.9 mm needle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a schematic illustration of a spinal cross section,according to embodiments of the present invention;

FIGS. 1B to 1D show a FAD placement procedure, according to embodimentsof the present invention.

FIGS. 1E to 1G show components of the catheter as in FIGS. 1B to 1D,according to embodiments of the present invention;

FIG. 2A shows an outer needle and a stylet, according to embodiments ofthe present invention;

FIG. 2B shows an inner needle and inner needle stylet, according toembodiments of the present invention;

FIG. 2C shows an inner needle comprising a Quincke type needle,according to embodiments of the present invention;

FIG. 2D shows an inner needle comprising a Whitacre type needle,according to embodiments of the present invention;

FIG. 2E shows an inner needle comprising a Levy type needle, accordingto embodiments of the present invention;

FIG. 2F shows an inner needle comprising a Sprotte type needle,according to embodiments of the present invention;

FIG. 2G shows a cross sectional view of a Sprotte type needle as in FIG.2F, according to embodiments of the present invention;

FIG. 2H shows a catheter exiting a side port of a Sprotte type needle asin FIGS. 2F and 2G, according to embodiments of the present invention;

FIG. 2I, shows a deflection angle of the catheter through a needle as inFIGS. 2F to 2H, according to embodiments of the present invention;

FIG. 2J shows a bend radius of the catheter as in FIGS. 2F to 2I,according to embodiments of the present invention;

FIGS. 3A and 3B show a catheter that comprises a radiopaque coil and aninflation lumen, in which the inflation lumen terminates proximal to aproximal end of an expandable balloon anchor, according to embodimentsof the present invention;

FIG. 3C shows inflation components and injection components connected toan inflation lumen and an injection lumen, respectively, according toembodiments of the present invention;

FIG. 3D shows components of a pressure relief valve, according toembodiments of the present invention.

FIG. 3E shows a wing nut connected to a Tuohy Borst connector, accordingto embodiments of the present invention;

FIG. 3F shows a pressure relief valve integrated into a stopcock,according to embodiments of the present invention;

FIG. 3G shows a stopcock as in FIG. 3F in an open position, according toembodiments of the present invention;

FIG. 3H shows a stopcock as in FIGS. 3F and 3G in a closed position,according to embodiments of the present invention;

FIG. 3I shows a coating on the inflation tube and a coating on theinjection tube, according to embodiments of the present invention;

FIGS. 4A to 4J show a method of delivering a catheter with an atraumaticinner needle comprising a side port, according to embodiments of thepresent invention;

FIG. 5 schematically illustrates a kit, according to embodiments of thepresent invention; and

FIGS. 6A and 6B schematically illustrate, a tapered inner needle,according to embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1A, relevant structures are shown of a spinalcross section 10 of a patient, according to embodiments of the presentinvention. Spinal cross section 10 includes a intervertebral disc D.Intervertebral disc D comprises an annulus fibrosis AF, or annulus, thatsurrounds a nucleus pulposus NP, or nucleus. A spinous process SP islocated near disc D. An arrow 12 points to the anterior of the patient.A skin S of the patient is located posterior to the spinous process SP.

Referring now to FIGS. 1B to 1D, a FAD placement procedure 100 is shown,according to embodiments of the present invention. FIG. 1B showsplacement of an outer needle 110. Outer needle 110 can be placed throughskin S while an outer needle stylet 120 is positioned inside outerneedle 110. Outer needle 110 may comprise a Discyphor outer needle, forexample a Discyphor Direct™ needle, available from Kyphon, Inc. ofSunnyvale, Calif. Outer needle 110 may be placed using fluoroscopicguidance to position the needle via a posterolateral approach. In someembodiments, outer needle 110 may be placed using the same approach andplacement as needles used for a standard provocative discography. Insome embodiments, outer needle 110 may be placed so as to extend to theannulus fibrosis of disc D, for example into the annulus fibrosis asshown in FIG. 1B. In some embodiments needle 110 can be inserted throughthe annulus into nucleus pulposus NP. Once outer needle 110 is inposition, stylet 120 may be removed.

FIG. 1C shows placement of an inner needle 130. Inner needle 130 and aninner needle stylet 140 may be placed inside outer needle 110. Underfluoroscopic guidance, inner needle 130 can be advanced through theouter needle 110, through annulus fibrosis AF and into nucleus pulposusNP of the disc. Stylet 140 of inner needle 130 can be removed after theneedle is properly positioned into nucleus pulposus NP of the disc.

FIG. 1D shows advancement of a catheter 150 through inner needle 130into the disc. While advancing catheter 150, fluoroscopy may be usedperiodically to ensure that inner needle 130 remains near the center ofnucleus pulposus NP and that inner needle 130 does not move beyond thisposition. Advancement of catheter 150 may pause when slight resistanceis felt as the distal tip of catheter 150 approaches an exit ramp of theinner needle 130, described herein below in detail. A radiopaque marker,which marks the center of a balloon 152, may be used to gauge theposition of the balloon relative to the annulus. Additionally, locationmay be confirmed by the color coded markers on the catheter, describedherein below in detail. Catheter 150 may comprise a balloon inflationlumen 154 and an injection lumen 156.

After the tip of the catheter is properly positioned, the outer needleand inner needle may be removed simultaneously using, for example, anover the wire technique, while the catheter lies in the nucleus of thedisc. The outer needle wing may be pulled back to ensure both needlesare removed simultaneously. A Tuohy Borst subassembly may be attachedwith a blue wing nut to the balloon inflation lumen on the catheter. Aradiopaque contrast agent, for example 1.5 cc of a 100% radiopaquecontrast agent, may be drawn into a 3 cc syringe with an attachedpressure relief valve as described herein below. The 3 cc syringe withthe attached pressure relief valve can be attached to a stopcock bytightening and/or turning a Luer-lock hub of the pressure relief valve.The radiopaque contrast can be injected through the inflation lumen toexpand the balloon.

Referring now to FIGS. 1E to 1G, components of catheter 150 as in FIGS.1B to 1D are shown, according to embodiments of the present invention.Catheter 150 may comprise a micro-catheter with a body 151 having aflexible shaft. In many embodiments, catheter body 151 comprises apolymeric tube having a central passageway, which receives the inflationtube and the injection tube. Catheter 150 comprises a length 150L.Length 150L of the catheter may comprise a range of lengths, for examplea range from about 30 to 62 cm. In this system, the catheter maycomprise a polymer balloon located near the distal tip. An anchor, forexample balloon 152, may comprise many anchors, for example as describedin U.S. Pat. App. Pub. No. 2005/0234425, the full disclosure of whichhas been previously incorporated herein by reference. An injection tube156 may extend from a proximal end of catheter 150 to a distal end ofthe catheter. Injection tube 156 may comprise an injection lumen 157. Aninflation tube 158 may extend from the proximal end of the catheter to adistal portion of the catheter near balloon 152. Inflation tube 158 maycomprise an inflation lumen 159. Injection tube 156 and inflation tube158 may comprise many materials, and in some embodiments may comprisestainless steel tubes that are contained inside a polymer shaft ofcatheter 150. The inflation lumen can be used for inflating anddeflating the balloon, and the injection lumen can be used for injectionof substances such as radiopaque contrast agents, local anesthetics,antibiotics and/or preservative-free saline solution. Bonds 154 mayattach balloon 152 to injection tube 156. Bonds 154 may comprise manytypes of bonds, for example UV adhesive bonds and/or heat bonds. Bonds154 may attach balloon 152 near a distal end of injection tube 156 andnear a distal end of inflation tube 158. Once catheter 150 has beenproperly positioned, balloon 152 can be inflated with a radiopaquecontrast medium, and balloon 152 may assist in maintaining propercatheter placement during the functional testing portion of theprocedure. Following this procedure, the balloon may be deflated tofacilitate removal of catheter 150.

In many embodiments, a radiopaque marker 155 may be disposed on acatheter 150, for example located centrally within balloon 152.Radiographic marker 155 may facilitate positioning of balloon 152 indisc D. Radiopaque marker 155 may comprise a many known radiopaquematerials.

Tuohy Borst adapters 170 may be connect to proximal ends of injectiontube 156 and inflation tube 158, for example after catheter 150 has beenplaced.

Injection tube 156 may comprise a color coded sheath 172, and inflationtube 158 may comprise a color coded sheath 174 to distinguish theinjection lumen from the inflation lumen. For example color coded sheath172 may comprise green to indicate injection tube 156 and injectionlumen 157, and color coded sheath 174 may comprise red to indicateinflation tube 158 and inflation lumen 159. Such colors are merelyillustrative and many combinations can be used, for example white can beused instead of green and blue can be used instead of red. In someembodiments, the injection lumen and/or tube can be distinguished fromthe inflation lumen and or tube by the length of the tubes. For example,the inflation tube and/or lumen may be shorter with a proximal end thatis distal to the proximal end of the inflation lumen, such that theballoon Tuohy Borst Adapter is distal to the injection Tuohy Borstadapter.

In many embodiments, catheter 150 comprises indicia over at least aproximal portion of the length of the catheter to indicate the positionof the distal end of the catheter in relation to a structure on theplacement instrument, for example the distal end of the inner needle.The indicia may comprise a scale formed, printed or etched on a surfaceof the catheter. In some embodiments, the indicia may comprise colorcoding, for example a color change that corresponds to a position of thecatheter in relation to the inner needle. Many indicia and codingschemes may be used to indicate the location of the catheter withrespect a placement instrument. In many embodiments, catheter 150 maycomprise color coded indicia to mark the location of catheter 150 as itpasses through the inner needle. The indicia on the catheter maycomprise reticules, scales gauges and the like, in addition to or incombination with color encoding, and many known methods of markingcatheters may be used to encode the position of the catheter in relationto the inner needle. In some embodiments, catheter 150 may compriseindicia with color encoding 160 to indicate the depth of the catheter inthe patient. The indicia comprising color encoding 160 may comprise aclear section 162 that may include balloon 152. Encoding 160 maycomprise a black section 160 to indicate that a distal tip of catheter150 has not yet reached a distal opening of the inner needle that exitsto the disc. Encoding 160 may comprise a green section 166. A distalboundary of green section 166 with black section 164 may indicate thatthe distal tip of catheter 150 is near the opening to the inner needle.Encoding 160 may comprise a black section 168. A transition from greensection 166 to black section 168 may indicate that the balloon hasexited the catheter port and that the distal tip of the catheter extendsfrom the opening into the disc by a pre-determined distance. Additionalindicia may be included that correspond to locations of additionalstructures of the catheter in relation to the inner needle.

In some embodiments, the catheter can be encoded to accommodate twoinner needle lengths, which can be particularly helpful when the twoinner needles are provided, for example provided in a kit, in a systemor separately. For example, the catheter may comprise a yellow, green,yellow color scheme, and the kit may comprise outer needles of 9 cm and13 cm. When the tip of the catheter is at the tip of the shorter of thetwo inner needles, the color transition of the catheter at the needlehub goes from yellow to green. When the tip of the catheter is at thetip of the longer of the two inner needles, the color transition of thecatheter at the needle hub goes from green to yellow.

Color coding can be performed in many ways. For example, the colorcoding could comprise printing a color with an ink, using a colored heatshrink, and/or laminating on a material to the tube. In someembodiments, color coding may comprise laser marking or laser etching.In addition to and/or in combination with color coding of the proximaltubes, the Tuohy Borst adapters may be color coded to indicate theirpurpose. In some embodiments, the inflation tube may be marked with acolor that matches the color of a Tuohy Borst adaptor, or other adapter,that is marked “inflation”. In some embodiments, the wing nuts may becolor coded to correspond with the adaptors. The injection tube may bemarked with a different color that matches the color of a Tuohy Borstadaptor that is marked “injection”.

FIG. 1F shows a cross sectional view of catheter 150 near a middlesection of the catheter, as in FIG. 1E. Catheter 150 comprises catheterbody 151. Injection tube 156 comprises injection lumen 157. Injectiontube 156 comprises an outer cross sectional size, for example outsidediameter 156OD, and an inner cross sectional size, for example an innerdiameter 156ID. Inner diameter 156ID corresponds to a cross sectionalsize of inflation lumen 157. Inflation tube 158 comprises inflationlumen 159. Inflation tube 158 comprises an outer cross sectional size,for example an outer diameter 158OD, and an inner cross sectional size,for example an inner diameter 158ID. Inner diameter 158ID corresponds toa cross sectional size of inflation lumen 157. Catheter 150 comprises anouter cross sectional size 150CS that corresponds to an outer diameter150OD. In many embodiments, outer cross-sectional size 150CS and outerdiameter 150OD may be no greater than 1.5 mm. In many embodiments, theouter cross sectional size and/or outer diameter can be sized to fitthrough a 0.9 mm, or 20 gauge, needle with an inner lumen of about 0.023inches, or about 0.5 mm, such that the catheter is capable of passingthrough the lumen of the inner needle. In specific embodiments, theouter cross sectional size and/or outer diameter may comprise a size ofabout 0.020 inches, or about 0.5 mm. In many embodiments, outer crosssectional size 150OS may be defined by catheter body 151.

The needles sizes described herein are merely illustrative according tosome embodiments, and one will recognize that many sizes of needles canbe used. In many embodiments, dimensions listed herein correspond toknown ISO standards and the normal ranges of needle dimensions inaccordance with these known ISO standards. For example, a metric sizeneedle of 0,7 corresponds to a 22 gauge needle with a range of outsidediameters from about 0.698 mm to about 0.730 mm and inside diameters ofabout 0.390 mm to about 0.522 mm. A metric size of 0,9 corresponds to a20 gauge needle with a range of outside diameters from about 0.860 mm toabout 0.920 mm and inside diameters of about 0.560 mm to about 0.687 mm.A metric size of 1,2 corresponds to a 18 gauge needle with a range ofoutside diameters from about 1.200 mm to about 1.300 mm and insidediameters of about 0.790 mm to about 1.041 mm.

FIG. 1G shows a cross sectional view of catheter 150 near a distalportion of the catheter with balloon 152 in an expanded configuration.Injection tube 156 comprises an outer diameter 156OD and inner diameter156ID. Balloon 152 comprises a cross sectional size, for example adiameter 152D. In a specific embodiment, diameter 152D may comprise asize of about 0.010 inches in the inflated configuration so as to anchorthe catheter in the disc interior. In an unexpanded and/or non-inflatedconfiguration balloon 152 may comprise a cross sectional size to fitthrough the inner needle.

In many embodiments, the catheter may comprise high axial forcetransmitting material, and the catheter may be reinforced with areinforcement component such as wire, thread, and/or filament toincrease axial strength. The reinforcement component may comprise ametal, for example at least one of stainless steel, tungsten, Elgiloy,platinum molybdenum, iridium or nitinol and/or other metals. In someembodiments, the reinforcement component may comprise alloys, forexample at least one of platinum-iridium, platinum-tungsten,molybdenum-rhenium, or tungsten-rhenium and/or other alloys. In someembodiments, the reinforcement component may comprise polymers such asPEEK, Kevlar or Dacron, and/or other polymers. In some embodiments thereinforcement component may comprise braids and/or twisted strands ofmetals, metal alloys and/or polymers. The reinforcement component may bedisposed on at least one of the catheter body, the injection tube or theinflation tube. The reinforcement component may be disposed over thecatheter body and/or tubes, and in some embodiments can be embedded insuch structures.

Embodiments of the present invention may use functional evaluation ofthe disc. Functional evaluation may comprise pain provocation andcareful assessment of the patient's response to pain. A substance can beinjected into the nucleus pulposus that may reduce pain perceived by thepatient. For example, if the patient reports a decrease in pain afterinjection of the substance into the disc, the disc may contribute topain previously perceived by the patient and the identified defectivedisc may be corrected surgically.

Several substances may be injected into the nucleus pulposus to performthe functional evaluation. In some embodiments, at least one of thefollowing substances can be introduced: an anesthetic; an analgesic; anantibiotic; a hydrating agent such as hypotonic saline, isotonic salineor hypertonic saline; a supportive agent such as a hydrogel,ethylene-vinyl alcohol copolymer, Dimethyl Sulfoxide or Tantalum; aprolotherapy agent such as sodium morrhuate, cod oil, phenol, mineralsor ethyl alcohol; and other agents such as collagen, stem cells,Osteogenic Protein-1, ethanol, alcohol, steroids, radio-opaque contrastagents, ultrasound contrast agent, Bone Morphogenetic Protein (BMP),BMP-2, BMP-4, BMP-6, BMP-7, BMP-12, Serotonin 5-HT2A receptorinhibitors, LMP-1, TIMP-1, TGF-1, TGF-2, Rofecoxib, Ketorolac,Glucosamine, Chondroitin Sulfate, Dextrose, DMSO, non-steroidalantiinflammatory drugs, ibuprofen, naprosyn, Bextra, Vioxx, Celebrex,indomethacin, botulinum toxin, capsaicin, vanilloid agonists, vanilloidantagonists, VR1, VRL-1, steroids, methylprednisolone or chymopapain;cells, cell fragments, tissue, tissue gragments; genetic material, suchas DNA, cDNA, RNA, mRNA, rRNA, siRNA, tRNA, plasmids, lentivirus,adenovirus, adeno-associated virus, or derivatives or fragments orsynthetic mimics thereof, cytokines, growth factors, differentiationfactors, hormones, ligands, receptors; intracellular regulatorymolecules, or transcription factors, or their agonists, antagonists,activators, or inhibitors, or derivatives or fragments of syntheticmimics thereof, matrix molecules such as fibrin, collagen,proteoglycans, glycosaminoglycans, polysaccharides, elastin, orderivatives or fragments or synthetic mimics thereof, matrix-regulatingmolecules such as crosslinking agents, link protein, metalloproteinases,or enzymes, or their activators or inhibitors, or derivatives orfragments or synthetic mimics thereof, drugs such as statins,purmorphamine, anti-inflammatory drugs; neurotransmitting agents orneurotoxic agents or their inhibitors; MRI contrast agents; bonefillers, bone graft materials, and bone graft substitutes such as boneautograft, bone allograft, anorganic bone matrix, demineralized bonematrix, calcium phosphate, tricalcium phosphate, calcium sulfate,hydroxyapatite, bioglass, polymers, or combinations thereof, additionalbiologic-based, biologic derived, or biologic-mimicking substances; andsubstances used for controlled release of any of the above substances,such as polymers, liposomes, self-assembling monolayers, tie-layermolecules, scaffolds, or gels, for example hydrogels.

In some embodiments, the substance can be injected to alter the pH ofthe nucleus. In specific embodiments directed to diagnosis, raising thepH can make the nucleus and surrounding tissues more basic so as tolower the threshold of triggering nociceptive receptors. Such pHlowering substances can also be injected into the patient in therapeuticembodiments.

Referring now FIG. 2A, an outer needle 210 and stylet 212 are shown,according to embodiments of the present invention. Outer needle 210 canbe used to access the disc, particularly, in the area adjacent to theintradiscal space to facilitate sequential placement of the inner needleand catheter into the intradiscal space. Outer needle 210 may comprisemany materials such as metal or plastic (e.g. retinol, cobalt chrome,PEEK, stainless steel). Outer needle 210 can comprise many sizes thataccess the tissue surrounding the disc, and outer needle 210 can besized to advance the inner needle to the interior of the disc. Outerneedle 210 may comprise many lengths, for example a 1.2 mm outsidediameter (18 gauge) needle 9 cm in length and a 1.2 mm outside diameterneedle 13 cm in length. In some embodiments, outer needle 210 may beprovided in a kit that includes two outer needles, for example a 1.2 mmdiameter needle 9 cm in length and an 1.2 mm diameter needle 13 cm inlength.

Stylet 212 can be sized to fit within a lumen of outer needle 210 andmay comprise a length that matches needle 210. Stylet 212 may comprisemany of the materials of outer needle 210. Outer needle 210 may comprisea bevel cut distal tip 216, and a stylet tip 218 may comprise a bevelcut that matches bevel cut needle tip 216. In many embodiments, outerneedle 210 comprises an insert to inhibit coring. The insert maycomprise at least one of a removable stylet, a trocar or an obturator,or the like, that can be removed from outer needle 210 after the outerneedle has been positioned, so as to inhibit coring when the outerneedle is placed in the tissue. Outer needle 210 comprises a length 211.Length 211 may comprise a range of lengths from about 3 to 30 cm and insome embodiments a range of lengths from about 3 cm to 20 cm. Outerneedle 210 comprises an inner size, for example an inner diameter 213.In many embodiments, inner diameter 213 may comprise a diameter no morethan about 1.7 mm.

Referring now to FIG. 2B, an inner needle 220 and an inner needle stylet222 are shown, according to embodiments of the present invention. Innerneedle 220 can be used to access nucleus pulposus NP of theintervertebral disc and is capable of passing through annulus fibrosisAF. Inner needle 220 can be used to perform provocative discography andmay facilitate placement of the catheter into the intradiscal space.Inner needle 220 may comprise an atraumatic needle that comprises ablunt tip 224 and a side port 226 that allows for delivery of theanchored catheter through side port 226. In many embodiments, thecatheter can be delivered through side port 226 without a guide wire.Inner needle 220 may comprise many materials such as metal or plastic(e.g. retinol, cobalt chrome, PEEK or stainless steel). Inner needlestylet 222 may comprise many materials similar to inner needle 220.Inner needle 220 may comprise many size suitable sizes to access thenucleus of the intervertebral disc and deliver the anchored catheter tothe intervertebral disc. Inner needle 220 comprises an outer crosssectional size, for example an outer diameter 221. In many embodiments,outer diameter 221 comprises a diameter no greater than about 1.5 mm.For example, outer diameter 221 of inner needle 220 may comprise a rangeof sizes from about 0.5 mm to about 0.9 mm. Inner needle 220 comprises alength 223. Length 223 of inner needle 220 may comprise a range oflengths from about 10 cm to about 30 cm. In some embodiments, innerneedle 220 may be comprised within a kit that includes two inner needlescomprising a 0.9 mm needle 18 cm in length and a 0.9 mm needle 10 cm inlength. Both needles may comprise atraumatic tips.

Inner needle 220 may comprise many types of needle tips that are adaptedto penetrate tissue. In many embodiments, needle 220 may comprise anatraumatic needle, for example a Sprotte needle commercially availablefrom Pajunk Medical Systems of Tucker, Ga., and distributed by Havel'sof Cincinnati Ohio, a Whittacre needle known in the art to performspinal blocks, and other atraumatic needles, for example as described inU.S. Pat. No. 5,573,519, entitled “Atraumatic needle for lumbarpuncture”, in the name of Zohmann, the full disclosure of which isincorporated herein by reference. In some embodiments, an atraumaticneedle may comprise pencil-point needle with a blunt tip and a sharppoint. In many embodiments, the atraumatic needle comprises a bluntneedle tip that separates the dura fibers, creating a small hole in thedura that closes. In some embodiments, the atraumatic needle maycomprise a side port that minimizes tissue tearing along edges of theport.

Referring now to FIG. 2C, detail of an inner needle comprising a Quincketype needle 230 is shown, according to embodiments of the presentinvention. Quincke type needle 230 may comprise a sharp beveled end andan oval port 232. Sharp beveled end 231 can cut through tissue and maybe desirable in some embodiments, for example tough tissue that anatraumatic with a non-cutting tip may have difficulty penetrating.

Referring now to FIG. 2D, an inner needle comprising a Whitacre typeneedle 234 is shown, according to embodiments of the present invention.Whitacre type needle 234 may comprise a blunt tip 237 with a sharp point235, such that the needle may comprise an atraumatic needle. Whitacretype needle 234 may comprise a side port 236. Side port 236 may comprisemany shapes including circular, oval, rectangular and combinationsthereof, such that side port 236 permits the catheter to exit the needlethrough side port 236.

Referring now to FIG. 2E, an inner needle comprising a Levy type needle238 is shown, according to embodiments of the present invention. Levytype needle 238 may comprise an annular needle 242 and an inner throughneedle 240. Inner through needle 240 may be removed after Levy typeneedle 238 has been positioned, such that the catheter can be passedthough annular needle 242.

Referring now to FIG. 2F, an inner needle comprising a Sprotte typeneedle 250, for example a special Sprotte needle, is shown, according toembodiments of the present invention. Sprotte type needle 250 maycomprise a side port 252. Side port 252 may comprise an elongate shape.For example, side port 252 can be shaped to permit the catheter to exitthrough the side of the inner needle with many elongate shapes includingoval, rectangular and elliptical shapes. Side port 252 can comprise alength 252L and a width 252W. In many embodiments, an inner size of theinner needle, for example an inner diameter 253, may be at least 0.38mm. Sprotte type needle 250 may comprise a blunt needle tip 254 with asharp point 156. Blunt tip 254 may comprise many blunt shapes, forexample a shape in the form of an ogive. Sprotte type needle 250 maycause less tissue damage than some other needle types. For example, theSprotte needle may not cause nerve damage if the needle hits nervesintraoperatively. Side port 252 may comprise all metal edges that aresmoothed, for example hand rounded, such that damage to a balloonpassing through the port is unlikely. In some embodiments, the Sprotteneedle may cause sufficiently less tissue damage than other needle typessuch that a larger diameter Sprotte needle may be used to place thecatheter, thereby facilitating passage of the catheter through theneedle.

Referring now FIG. 2G, a cross sectional view of Sprotte type needle 250as in FIG. 2F is shown, according to embodiments of the presentinvention. The inner needle comprises an inner lumen with a size thatcorresponds to inner diameter 253 of the inner needle. Side port 252 maycomprise a depth 252D cut into the inner needle. Side port 252 ispositioned near a ramp 259. Ramp 259 may guide the catheter tip towardside port 252. Ramp 259 may be formed in many ways, for example with amaterial 258. Material 258 may comprise many materials, for examplematerials similar to the inner needle and stylet. In some embodimentsmaterial 258 may comprise a rigid filler material, for example epoxy.Side port 252 can be adapted to slide along the catheter while the sideport is retracted proximally through the annulus in many ways includingat least one of width 252W, length 252L or cut depth 252D.

Referring now to FIG. 2H, a catheter 260 is shown exiting side port 252of Sprotte type needle 250 as in FIGS. 2F and 2G, according toembodiments of the present invention. Catheter 260 may comprise many ofthe catheter components described above. For example, catheter 260 maycomprise a FAD catheter with an expandable balloon that can fit throughside port 252. In many embodiments, catheter 260 comprises a flexibledistal tip that is capable of bending so as to pass through side port252 upon deflection by ramp 259.

Referring now to FIG. 21, a deflection angle 262 of catheter 260 througha needle port as in FIGS. 2F, 2G and 2H is shown, according toembodiments of the present invention. Deflection angle 262 may comprisean angle between the inner needle with the side port, for exampleSprotte needle 250, and the catheter that extends from the side porttoward the distal end of the catheter. In some embodiments, angle 262comprises a range from about 5 degrees to about 35 degrees and maycomprise a range from about 10 degrees to about 15 degrees. Angle 262may comprise a predetermined angle determined by at least one of length252L of the side port, width 252W of the side port and an angle ofinclination of ramp 259.

Referring now to FIG. 2J, a bend radius 264 of catheter 260 is shown,according to embodiments of the present invention. Bend radius 264comprises a known method of measuring the flexibility of a catheter.Bend radius 264 can be measured by forming a loop on the catheter andpulling on the catheter. Bend radius 264 may comprise a range from about5 to 15 mm. In specific embodiments, bend radius 215 can be about 8 mm.In some embodiments, bend radius 264 approximates a slope comprising alength 268 and a height 266 that corresponds to deflection angle 262. Inspecific embodiments, the bend radius corresponds to the length, widthand cut depth of the side opening in the catheter.

Referring now to FIGS. 3A and 3B, a catheter 310 is shown that comprisesa radiopaque coil 320, an inflation lumen 330 and an injection lumen350. Catheter 310 may comprise a catheter body 311 that comprises aproximal portion 312 and a very flexible distal portion 314. Flexibledistal portion 314 may terminate distally at distal end 315 of thecatheter. Inflation lumen 330 can comprise a proximal end 332 and adistal end 334. A tube 331 can define inflation lumen 330. An injectiontube 351 can define injection lumen 350. In many embodiments, flexibledistal portion 314 may be more flexible than the portion of the catheterthat includes inflation tube 331. Catheter body 311 may comprise apolymeric tube having a central passage which receives the inflationtube and the injection tube. Radiopaque coil 320 may comprise a proximalend 322 and a distal end 324, such that coil 320 extends over flexibledistal portion 314.

Radiopaque coil 320 can facilitate placement of the catheter with x-rayand/or fluoroscopy and may provide safety advantages. In manyembodiments, the coil can easily flex with distal end portion 314. Inspecific embodiments, the coil may extend from a distal tip of theinjection tube 351T to proximal portion 312 of the catheter so as toprovide safety advantages. For example, if the distal shaft of thecatheter comprising flexible distal portion 314 were to break, the coilmay permit the broken catheter to be removed as one piece as the coilmay retain the broken distal portion, such that the broken distalportion may be removed with the intact proximal portion of the catheter.In some embodiments, the flexible coil may extend from distal tip 351Tto a proximal portion of the catheter located near the distal end ofinflation tube 331, so as to provide similar retention of the distalportion.

Catheter 310 may comprise an inflatable balloon anchor material 340.Balloon anchor material 340 may comprise a proximal portion 342, adistal portion 344 and an expandable anchor portion 346 therebetween.Proximal portion 342 of balloon anchor material 340 can be fixed toinflation tube 331 with many techniques and/or substances, for exampleadhesives and/or curing as described above. Distal portion 344 ofballoon anchor material 340 can be connected to injection tube 351 withmany techniques and or substances as described above. In manyembodiments, the proximal and distal portions of the balloon materialmay be thicker such that these portions may not expand substantiallyduring inflation of the balloon and may not anchor the catheter. In someembodiments, the expandable anchor portion of the balloon material maycomprise folds and may be thinner than the proximal and distal portionssuch that the expandable anchor portion can expand substantially toanchor the catheter with the balloon.

In many embodiments, distal end 334 of inflation tube 331 and inflationlumen 330 may terminate proximal to expandable anchor portion 346 ofballoon anchor material 340, such that distal portion 314 of catheter310 can be flexible. For example, inflation tube 331 may terminate withdistal end 334 a distance from distal end 315 of the catheter in a rangefrom about 3.8 to 7.6 cm. Such a distance can be sufficient in manypatients to position the balloon anchor centrally in the disc space, forexample centrally in the nucleus pulposus, and have distal end 334 ofthe inflation tube and the inflation lumen positioned away from theannulus and nerve roots. In some embodiments, the distal end of theinflation tube may lie at least about 5.5 mm proximally of the distaltip of the catheter body. In many embodiments, injection tube 351extends distally beyond the distal end of inflation tube 331 andterminates near a distal tip 311T of the catheter body. In specificembodiments, injection tube 351 extends distally beyond a distal end ofthe expandable portion of the anchoring balloon by a distance of atleast about 2 mm.

In some embodiments, proximal portion 324 of balloon anchor 340 does notexpand substantially and may comprise a lumen 347. Lumen 347 can providefluid communication with expandable portion 346, inflation tube 331 andinflation lumen 330, such that fluid from inflation tube 331 can passthrough lumen 347 to expandable portion 346 to inflate the expandableportion.

Referring now to the schematic illustration of FIG. 3C, inflation andinjection components 380 are shown connected to an inflation lumen andan injection lumen, respectively, according to embodiments of thepresent invention. Catheter 310 may comprise inflation lumen 330 andinjection lumen 350, as described above. A wing nut 352 can be connectedto a Tuohy Borst connector 354. Wing nut 352 can facilitate attachmentof at least some of components 380. Tuohy Borst connector 354 canconnect to the inflation lumen and tube. A stopcock 356 can be connectedto Tuohy Borst connector 354. Stopcock 356 comprises an isolation valvethat can be used to shut off fluid flow to inflation lumen 330 andcomponents 380 that are distal to stopcock 356. In some embodiments, aone way valve, for example a check valve 358, may be connected tostopcock 356. Check valve 358 may ensure that fluid flows one way in aproximal to distal direction, as shown by arrow 359. In someembodiments, components 380 may include a pressure relieve structurethat comprises a pressure relief valve 370. Pressure relief valve 370can be connected to stopcock 356 and check valve 358, such that fluidthat exits check valve 358 can enter either stopcock 356 or pressurerelief valve 370. A syringe 360 can be connected to check valve 358. Inmany embodiments, fluid flow from a proximal to a distal direction maycomprise downstream flow, and fluid flow from a distal to proximaldirection may comprise upstream fluid flow.

Syringe 360 can be connected to inflation lumen 330 such that syringe360 can inflate the balloon anchor. In many embodiments, fluid thatpasses through check valve 358 enters stopcock 356 to inflate theballoon until the balloon reaches a desired predetermined pressure. Whenthe inflation lumen and balloon reach the desired predeterminedpressure, pressure relief valve 370 can open, such that fluid passesthrough pressure relief valve 370 to an exit port in a visible mannersuch that the clinician knows the desired predetermined pressure hasbeen reached. In embodiments that include one-way check valve 358, theclinician may release syringe 360 and then close the valve stopcock 356.Some embodiments may not include check valve 358, and the clinician mayclose the valve of stopcock 356 while pressure is applied to syringe 360to retain pressure and prevent reverse flow from the balloon back intothe syringe. Once stopcock 356 is closed, the balloon may be subjectedto additional pressure up to the burst pressure of the balloon.

Although the components are shown between syringe 360 and inflationlumen 330 in an illustrated order, many additional componentcombinations and/or component orders are possible. For example, thepressure relief valve can be installed distal to the stopcock, such thatthe balloon can vent through the pressure relief valve after thestopcock is closed. This may allow the balloon to release fluid throughthe pressure relief valve in response to the balloon being subjected toadditional pressure after the stopcock has closed, for example when thepatient moves. In some embodiments, the pressure relief valve may belocated on the stopcock.

Components 380 may comprise several components that are connected toinjection lumen 350. A Tuohy Borst connector 364 can be connected toinjection lumen 350. A wing-nut 362 can be connected to Tuohy Borstconnector 364. In some embodiments, a one-way valve, for example checkvalve 366, can be connected to the Tuohy Borst connector to provideone-way fluid flow in a proximal to distal downstream direction asindicated by arrow 367. The one-way valve can prevent upstream backflowof substances through the injection lumen. A connector 368 can beconnected to a syringe to inject substances into the disc throughinjection lumen 350.

Referring now to FIG. 3D, components of pressure relief valve 370, whichcomprises check valve, are shown according to embodiments of the presentinvention. Pressure relief valve 370 comprises an opening 371 in fluidcommunication with syringe 360 such that fluid from syringe 360 can passinto pressure relieve valve 370 under pressure. Pressure relive valve370 comprises a ball 372 that contacts a seat 374 to form a seal. Aspring 376 applies pressure to ball 372. Spring 276 can be selected suchthat ball 372 with separate from seat 374 at a selected and/orpredetermined pressure, for example about 150 psi. In many embodiments,the selected and/or pre-determined pressure corresponds to the desiredinflation pressure to the balloon. In specific embodiments, a balloonmay have a rated pressure of 300 psi, and spring 376 selected such thatpressure relief valve 370 releases fluid at about 150 psi. In someembodiments, the predetermined pressure may comprise a range from about680 kPa to about 1620 kPa. Arrow 379 indicates the direction of fluidflow, for example liquid fluid flow, into an exit port 378 of thepressure relief valve. In many embodiments, fluid flows out exit port378 such that the fluid is visible to the user and the user candetermine that pressure relieve valve 370 has cracked open and inflationlumen 360 and the balloon have reached the selected and/or predeterminedpressure.

Pressure relief valve 370 may comprise a check valve that can only passfluid in one direction. Pressure valve 370 comprises many componentsthat are similar to check valve 358 and check valve 366 that provideone-way fluid flow. In some embodiments, the check valves that are usedto provide one way flow may comprise springs that allow the one-waycheck valves to crack open and pass fluid with relatively littlepressure, for example 69 kPa (10 psi), as compared to pressure reliefvalve 370 that may pass fluid at 1030 kPa (150 psi).

Referring now to FIG. 3E, wing nut 352 is shown connected to Tuohy Borstconnector 354, according to embodiments of the present invention. Wingnut 352 can slide onto Tuohy Borst connector 354. Wing nut 353 comprisesa slot opening 353 sized to pass lumen 330 of tube 331. Slot opening 353permits removal of wing nut 352 over lumen 330 of tube 331, such thatwing nut 352 can be removed from the catheter after tightening the TuohyBorst connector while the Tuohy Borst connector is attached to thelumen. In many embodiments, wing nut 352 comprises a plastic wing nutmade by injection molding, for example known ABS plastic injected into amold using know injection molding techniques.

Referring now to FIG. 3F, a pressure relief valve 390 is shownintegrated into a stopcock 380, according to embodiments of the presentinvention. Stopcock 380 can be connected to a syringe 381. Pressurerelief valve 390 can be connected to the fluid path while the valve isopen and isolated from the fluid path when the valve is closed. In someembodiments, the pressure relief valve and stopcock may comprise partsof the inflation syringe.

Referring now to FIG. 3G, stopcock 380 as in FIG. 3F is shown in an openposition, according to embodiments of the present invention. Stopcock380 comprises a fluid inlet 382, a fluid outlet 384 and a cylindricalmember 386 therebetween. Cylindrical member 386 comprises a channel 388.Channel 388 extends between inlet 382 and outlet 384 while the stopcockis open, such that inlet 382 is in fluid communication with outlet 384.Channel 388 extends to pressure relief valve 390. Pressure relief valve390 may comprise a ball 394 and seat 392, similar to the ball and seatdescribed above. Pressure from fluid in channel 388 can open thepressure relief valve. Pressure relief valve 390 may comprise a springthat allows valve 390 to open at a selected and/or predeterminedpressure, as described above. A handle 389 can be rotated to close thestopcock and isolate pressure valve 390.

Referring now to FIG. 3H, stopcock 380 is shown in a closed positionaccording to embodiments of the present invention. Inlet 382 can beisolated from outlet 384 with rotation of handle 389, such that channel388 does not connect inlet 382 with outlet 384. Handle 389 can also berotated to open stopcock 380 such that channel 388 connects inlet 382,outlet 384 and valve 390.

The pressure relief valve may be located in many positions. In someembodiments, the pressure relief valve may be integrated into otherareas of the components, such as in the body of the stopcock, or on aseparate opening of the stopcock. The pressure relief valve may also beintegrated into the syringe and/or as a separate device. In someembodiments, the pressure relief valve may comprise adjustable pressurerelief valves, and the pressure relief valve may comprise visual and/orauditory signals to alert the user when the relief pressure has beenreached. In some embodiments, the pressure relief valve may comprise aseparate pressure relief valve, for example as available from Qosina ofEdgewood, N.Y.

Referring now to FIG. 31, a coating 392 is shown on inflation tube 331and a coating 394 is shown on injection tube 351 of catheter 310,according to embodiments of the present invention. During the functionaltesting portion of the test, the FAD catheter can be secured to thepatient, and the patient can be asked to perform activities that provoketypical and/or representative pain for the patient. During theseactivities it is possible that the proximal ends of the tubes could berepeatedly bent. If these tubes are excessively deformed, it is possiblethat the tube material could fatigue and break. If the injection tubebreaks, injections may no longer be possible. If the balloon tube breaksthe balloon may lose inflation pressure, possibly allowing the cathetertip to migrate from the disc space. The inflation and/or injection tubescan be reinforced with coatings to prevent fracture, and in someembodiments to maintain integrity of the tubes after the tubes fracture.Coating 392 and/or coating 394 may comprise PEEK, PET and/or otherpolymers known in the art. These coatings can increase rigidity of thetubes so as to decrease the possibility of fracture. In someembodiments, the tubes, for example the inflation tube, can be coatedwith the polymer such that the coating can withstand high presser afterthe tube fractures and the fluid does not leak through the coating andis retained by the coating. The polymer coating may be attached withadhesive, melted to the tube and/or can be made of a heat shrinkmaterial that is shrunk onto the tube.

As noted above, the proximal ends of the tubes may be exposed torepeated stresses that may potentially cause the tubes to fracture fromfatigue. In some embodiments, the inflation and injection tubes maycomprise heat treated metal and/or metal alloy. In specific embodiments,the tubes may comprise stainless steel tubes that can be supplied in afully hardened treatment state. Although fully hardened stainless steelcan be stiff, strong, and fairly elastic, such stainless steel can havea moderate resistance to fatigue loading. In some embodiments, the tubescan be fully and/or partially annealed to improve the fatiguecharacteristics. Specific embodiments may comprise partially and/orfully annealed tubes, for example selectively annealed tubes. Suchembodiments may comprise a distal portion of the tube that is fullyhardened and a proximal portion of the tube outside the patient that isannealed.

Referring now to FIGS. 4A to 4J, a method 500 of delivering a catheteris shown that uses an atraumatic inner needle comprising a side port,according to embodiments of the present invention. A step 405 positionsan outer needle 407, or introducer needle. Outer needle 407 manycomprise wings 408 to facilitate handling. Outer needle 407 can bepassed through a skin S with a stylet 409 positioned inside outer needle407, such that outer needle 407 and stylet 409 are positioned nearspinal process SP and outside annulus fibrosis AF and nucleus pulposusNP. In some embodiments, stylet 409 may comprise an obturator, that canobstruct a hole such as the lumen of outer needle 407 which protrudesthrough the distal opening of the outer needle 407. The obturator maycomprise an atraumatic rounded and/or blunt tip with a sharp point, asdescribed above, so as to penetrate tissue with minimal cutting and/ortrauma. Stylet 409 can then removed from outer needle 407. A step 410passes an inner needle 412 through outer needle 407, such that a distaltip of inner needle 412 can be advanced into the interior of the discspace, for example into nucleus pulposus NP. In some embodiments, innerneedle 412 comprises a Special Sprotte needle with a blunt atraumatictip and side port, as described above. A step 415 may perform atraditional provocative discography, and then flush inner needle 412with saline. The traditional discography may comprise injection of asubstance 416, for example a contrast agent as described above, throughinner needle 412. A step 420 delivers a catheter 422 to a side portdistal opening 414 of inner needle 412. Catheter 422 may comprise adistal radiopaque marker, as described above. Catheter 422 may comprisedepth coding, for example color coding, as described above. Inner needle412 may comprise a hub 416. Color and/or color changes on catheter 422near inner hub 416 can indicate a position of a distal tip of thecatheter in relation to the inner needle opening and/or spinal disc, asdescribed above. A step 425 advances a distal end 424 of catheter 422just past a ramp 418 near side port 414 of inner needle 412. A step 430removes both inner needle 407 and outer needle 412 simultaneously, forexample using over the wire technique, such that distal end 424 ofcatheter 422 remains near the interior of the disc. The distal portionof catheter 422 that comprises the radiopaque marker and balloon can beadapted to slide along ramp 418 and through side port 418 while theinner needle and outer needle are retracted proximally, such that thecatheter tip remains near the interior of the disc. A step 435 fullyretracts outer needle 407 and inner needle 412 proximally such thatcatheter 422 remains in place in the interior of the disc and the innerand outer needle are removed from skin S of the patient. A step 440attaches a Tuohy Borst adapter 443 and a Tuohy Borst adapter 444, andinflates a balloon 442. Adapter 443 can be connected to an injectionlumen 441A, as described above. Adapter 444 can be connected to aninflation lumen, as described above. In some embodiments, step 440 canbe facilitated. For example, some components can be packaged assembledsuch that the components are removed from a kit in a pre-assembledconfiguration. Injection lumen 441A can be connected to a pre-assembledcheck valve and/or wing nut with adapter 443. The wing nut can withadapter 443 can be color coded to injection lumen 441A. Inflation lumen441B can be connected to a pre-assembled wing nut, pressure relief valveand/or stop cock with adapter 444. The wing nut with adapter 444 can becolor coded to inflation lumen 441B. Such coding can be explained in theinstructions for use. A step 445 can tie down catheter 422 with tie down446, for example an Epi-Guard tie down and/or custom tie downs, known inthe art and commercially available from Lina Medical of Copenhagen,Denmark and Dyna Medical Corporation of Ontario, Canada. A step 450performs a functional test on the patient. The functional test mayinclude many known functional techniques, including having the patientassume a painful position and injecting a substance, as described above,into the disc to identify the disc as a source of pain in response tothe patient reaction to the injected substance.

It should be appreciated that the specific steps illustrated in FIGS. 4Ato 4J provide a particular method of accessing the interior of anintervertebral disc, according to an embodiment of the presentinvention. Other sequences of steps may also be performed according toalternative embodiments. For example, alternative embodiments of thepresent invention may perform the steps outlined above in a differentorder. Moreover, the individual steps illustrated in FIGS. 4A to 4J mayinclude multiple sub-steps that may be performed in various sequences asappropriate to the individual step. Furthermore, additional steps may beadded or removed depending on the particular applications. One ofordinary skill in the art would recognize many variations,modifications, and alternatives.

Referring now to FIG. 5, components of a kit 500 are shown, according toembodiments of the present invention. A Functional AnestheticDiscography Procedure may use a system 520 that comprises the componentsof kit 500. Such components can be used to deliver radiopaque contrast,local anesthetics, and/or saline solution to the intradiscal space, thedosage amounts can vary may comprise a single dose or continuousadministration.

Components of kit 500 may comprise: a catheter 501; a 1.2 mm (18 gauge)Discyphor Direct™ Outer Needle 502 with wing; a 0.9 mm (20 gauge)Discyphor Direct™ Inner Needle 503; a stopcock (one-way) 504; a 3 ccsyringe with a pressure relief valve 505; two 1 cc syringes 506; twoTouhy-Borst 507; two Touhy-Borst Tie-Downs 508; two wing nuts 509; aCatheter Tie-Down (Epi-Guard) 510; a package of sterile labels 511; andinstructions for use (IFU) 512. At least some of the components of kit500 are commercially available from Kyphon, Inc. of Sunnyvale, Calif.Catheter 501 may comprise many of the catheters described above, forexample catheters that can be delivered through a side port of anatraumatic needle. The 1.2 mm outer needle 502 with wing may comprise anouter needle, as described above. The 0.9 mm inner needle 503 manycomprise inner needles described above, for example a special SprotteNeedle as described above. Stopcock (one-way) 504 may comprise a one-waycheck valve as described above. The 3 cc syringe with a pressure reliefvalve 505 may comprise a pressure relieve valve as described above. Thetwo 1 cc syringes 506 may comprise commercially available and known 1 ccsyringes. The two Tuohy Borst 507 may comprise known commerciallyavailable Tuohy Borst adapters as described above. The two Tuohy BorstTie-Downs 508 may comprise known commercially available Tuohy Borst TieDowns. The two wing nuts 509 may comprise injection molded wing nuts, asdescribed above The Catheter Tie-Down (Epi-Guard) 510 may comprise aknown commercially available tie-down as described above. The package ofsterile labels 511 may comprise known commercially available sterilelabels. Instructions for use (IFU) 512 may comprises printed and/orother instructions with figures that show how to use the components ofkit 500.

In some embodiments, components of the kit, or system, can be soldseparately. For example, the inner and outer needle can be provided “ala carte” and separate from other components, such that the inner andouter needle are provided together as a pair comprised within a sterilepackage. In specific embodiments, a 89 mm (3.5″) long by 1.2 mm (18 g)outer needle can be provided with a 178 mm (7″) long by 0.9 mm (20 g)wide inner needle in a sterile package. In a specific embodiment a 127mm (5″) long by 0.9 mm (18 g) wide outer needle can be provided with a203 mm (8″) long by 0.9 mm (20g) wide inner needle in a sterile package.

Many of the above metal structures, for example stylets, tubes,guidewires and radiopaque coils, may comprise the following advancedmetals and alloys thereof: tungsten, rhenium, molybdenum, tantalum andpalladium. In specific embodiments, the structures comprise at least oneof the following advanced metal alloys: tungsten-rhenium,tungsten-carbide and molybdenum-rhenium. In specific embodiments, theabove structures comprise cobalt-chromium, for example acobalt-chromium-nickel commercially available and known as Elgiloy™.Work in relation to embodiments of the present invention indicates thatstructures comprising tungsten-rhenium, tungsten carbide,molybdenum-rhenium and pure rhenium can provide much stiffer, strongerand radiopaque stylets, tubes, guidewires and radiopaque coils than forexample a Super Stiff Amplatz guidewire. Material parameters that canbenefit from such advanced metals and alloys include overall strength,radiopacity, tensile strength, axial strength, stiffness, elongation atbreak, modulus of elasticity, Poisson's ratio, shear modulus, electricalresistivity, magnetic susceptibility, specific heat capacity, or thermalconductivity. Such advanced metals and metal alloys can provide reducedcatheter sized, with greater pushability, radiopacity, and overallstrength, thereby providing smaller, easier to use and less invasivedevices. In some embodiments, needles and stylets comprising suchadvanced metals and advanced alloys may comprise thinner needle andstylet walls that can penetrate tissue with less needle force, canprovide more pushability, strength and memory than, for example, astainless steel needle or stylet. Known metallurgy techniques, forexample annealing, can be used to treat the advanced metals and metalalloys to provide the desired material properties.

In some embodiments, the advanced metal or advanced metal alloys can beused in many interventional fields such as orthopedics, GI, peripheral,cardiovascular, neurovascular, and other percutaneous procedures, forexample those in which catheters are used with active strengtheningwires. In a specific embodiment, the advanced metals and advanced metalalloys can be used with endoscopic retrograde cholangio-pancretography(ERCP). With ERCP catheter size can be very important when cannulatingthe Sphincter of Oddi (Major Papilla) and accessing body lumens such asthe bile or pancreatic duct. In some embodiments, the advanced metal andmetal alloys can be used to reinforce a catheter body and/or otherstructures so as to alleviate kinking and/or bending that may arise atthe elevator of an endoscope, for example with an ERCP catheter. In someembodiments, the advanced metal and/or metal alloys can be used withmedical device implants, for example orthopedic implants such as pediclescrews, rods, and cages. In specific embodiments, embolism coils maycomprise the advanced metals and metal alloys described above to providesignificant radiopacity.

Referring now to FIGS. 6A and 6B, a tapered inner needle 600 is shown,according to embodiments of the present invention. Inner needle 600 canbe sized to pass through a lumen of the outer needle and may comprise aninner needle stylet, as described above. In many embodiments, taperedinner needle comprises a tapered outside diameter along the needle shaftwhile the inside diameter remains substantially constant. Inner needle600 comprises a proximal portion 610, a tapered middle portion 620, adistal portion 630, and a length 602. In between the proximal end anddistal end, inner needle 600 can be sized to fit within the outerneedle. The inner needle can comprise proximal dimensions sufficient forstiffniess and distal dimensions to penetrate the annulus with minimaltrauma. For example, middle portion 620 may comprise a tapered middlesection 622 that extends beyond the outer needle when then the innerneedled is placed. This taper permits the distal portion of the innerneedle to be thin so as to minimize tissue damage and permits theproximal portion to be thicker and provide stiffness. Inner needle 600may comprise thin walled tubes made from known polymers such as PEEK,polyimide (e.g. Ultem™, polyether imide), poly carbonate, polyetherimide(PEI, Ultem®), polyphenylsulfone (PPSU, Radel R®), Acetal (POM,Delrin®), PPS (Fortron®, Ryton®), or polyimide (Vespel®).

Inner needle 600 may comprise an injection molded needle using knowninjection molding techniques and materials. Alternatively inner needle600 may be formed using heat (created with IR/UV/RF/or electricalresistance) and formed from extrusion(s) using known forming techniquesand materials. In some embodiments, the injection molded needle maycomprise an atraumatic tip with side port and ramp, as described above.In some embodiments, the tapered needle may comprise stainless steel.However, work in relation with the present invention suggests thepolymer inner needle can be less brittle than comparable thin walledstainless steel tubes, and the polymer inner needle may require morecycles and/or force to break than the stainless steel needle tube, evenafter the polymer needle has kinked. Such characteristic can be helpfulto avoid the unlikely event that such broken needle could break in thepatient. In some embodiments, the improved material properties of suchpolymers permit the design of tapered inner needles with a smalleroutside diameters that may cause less trauma to the penetrated disc.Also, known injection molding or folding techniques can make the polymerneedle easier to manufacture.

Proximal portion 610 comprises a lug 612 for engaging the needle hub.Lug 612 comprises an outer diameter 611. Proximal portion 610 comprisesan incline 614 at an angle to fit engage the hub. A distal section 616of proximal portion 610 comprises a size to fit within the outer needle,for example an outer diameter 616 OD. A lumen of inner needle 600comprises an inner diameter 6161D. Distal section 616 of proximalportion 610 comprises a thickness 616T to provide strength and/orstiffness. Proximal portion 610 comprises an opening and lumen sized toreceive an inner needle stylet, as described above. The inner needlestylet can stiffen the inner needle. A distance 613 from the proximalend of the needle to the distal section of the proximal portion can beabout 2.5 mm, in some embodiments. Outside diameter 616OD can be sizedfrom about 0.7 mm to about 1.1 mm, for example from about 0.889 to about0.934 mm, and inside diameter 616ID can be from about 0.5 mm to about0.8 mm, for example from about 0.648 to about 0.712 mm. Thickness 632Tcan be from about 0.1 mm to about 0.15 mm, for example about 0.127 mm.

Middle portion 620 comprises a proximal section 622, a middle section624 and a distal section 626. Proximal section 622 may remain inside theouter needle when placed in the patient. Thus proximal section 622 maycomprise dimensions similar to the distal section 616 of proximalportion 610 that fit inside the outer needle. Middle section 622 maycomprise a taper where the outside diameter of the inner needle becomessmaller distally and the inside diameter remains substantially constant.In many embodiments, middle section 624 extends slightly beyond theouter needle tip when the inner needle is positioned, so as to minimizetissue damage and provide stability. The taper of distal section 624extends over a distance 625. Distance 625 can be about 2.5 mm (0.1)inches, in some embodiments.

Distal portion 630 comprises a proximal section 632, a middle section634 and a distal section 636. Distal portion 630 comprises asubstantially constant inside diameter, outside diameter and tubethickness that extends along proximal section 632, middle section 634and distal section 636. Proximal section 632 comprises an insidediameter 632ID, an outside diameter 632OD and a tube thickness 632T. Inmany embodiments, distal section 626 of middle portion 620 comprisesdimensions (e.g. tube thickness, inside diameter and outside diameter)that are substantially similar to distal portion 630. This narrow distalportion of the needle extends over a distance 627. In some embodimentsdistance 627 can extend from about 29 mm to about 35 mm, for exampleabout 32 mm. In some embodiments, outside diameter 632 OD can be fromabout 0.6 mm to about 1 mm, for example from about 0.813 mm to about0.823 mm, and inside diameter 632ID can be from about 0.5 mm to about0.8 mm, for example from about 0.648 mm to about 0.673 mm. Thickness632T can be from about 0.05 to about 0.1 mm, for example about 0.076 mm.

In many embodiments, outside diameter 632OD on the distal portion issmaller than outside diameter 616OD on the proximal portion while theinside diameter (e.g. 616ID and 632ID) remains substantially constant,such that thickness 632T on the distal portion is smaller than thickness616T that fits inside the outer needle.

While the above is a complete description of the preferred embodimentsof the present invention, other embodiments may fall within the spiritand scope of the invention. Therefore, the scope of the presentinvention should be determined with reference to the appended claimsalong with their full scope of equivalents.

1. A method for positioning a catheter in an interior of anintervertebral disc, said method comprising: percutaneously advancing afirst needle through a skin toward the intervertebral disc; advancing asecond needle through a lumen of the first needle to penetrate through asurface of the intervertebral disc into the interior of the disc, andadvancing a catheter through a lumen of the second needle into theinterior of the disc.
 2. A method as in claim 1, wherein the firstneedle is advanced with a stylet or obturator in its lumen, furthercomprising removing the stylet or obturator after the first needle hasreached the surface location.
 3. A method as in claim 2, wherein thefirst needle has an inner diameter of no more than 1.7 mm and a lengthin the range from 3 cm to 20 cm.
 4. A method as in claim 1, wherein thesecond needle is advanced with a stylet or obturator in its lumen,further comprising removing the stylet or obturator after the secondneedle has reached the interior of the disc.
 5. A method as in claim 4,wherein the second needle has an outer diameter no greater than 1.5 mmand an inner diameter of at least 0.38 mm.
 6. A method as in claim 5,wherein the catheter has an outside cross sectional size no greater than1.5 mm and a length in the range from 30 cm to 62 cm.
 7. A method as inclaim 1, further comprising observing indicia on a proximal portion ofthe catheter as the catheter is advanced through the lumen of the secondneedle, wherein the indicia indicate a position of the catheter relativeto a distal end of the second needle so that a user will know when thecatheter has passed from the second needle into the interior of thedisc.
 8. A method as in claim 7, wherein the indicia comprise a scaleformed on the exterior of a proximal portion of the catheter.
 9. Amethod as in claim 7, wherein the indicia comprise a color change on thecatheter.
 10. A method as in claim 1, wherein the catheter is advancedthrough a side port of the second needle to advance the catheter intothe interior of the disc.
 11. A method as in claim 10, wherein thecatheter is advanced into the interior of the disc through the side portat a deflection angle of about 5 to 35 degrees from the second needle.12. A method as in claim 1, further comprising retracting the secondneedle such that the catheter slides along a side port of the secondneedle and a distal tip of the catheter remains in the interior of thedisc.
 13. A method as in claim 12, wherein the first needle is retractedto retract the second needle and slide the side port along the catheter.14. A method as in claim 12, further comprising inflating an expandableballoon to anchor the catheter in the disc interior after the secondneedle has been retracted.
 15. A system for positioning a catheter in anintervertebral disc of a patient, the intervertebral disc having anannulus and a nucleus, the system comprising: a needle sized to extendthrough a skin of the patient and through the annulus into the nucleus,the needle comprising an inner lumen and a closed distal tip; and acatheter sized to fit inside the lumen of the needle and extend into thenucleus.
 16. The system as in claim 15, wherein the catheter comprises aballoon anchor sized to pass through the lumen into the nucleus.
 17. Thesystem as in claim 15, wherein the distal tip of the needle comprises atapered profile.
 18. The system as in claim 15, wherein the distal tipof the needle comprises an atraumatic needle tip.
 19. The system as inclaim 15, wherein the closed distal tip of the needle comprises a sideport and wherein the lumen extends to the side port.
 20. The system asin claim 19, wherein the needle is adapted to slide along the catheterand out the side port while the atraumatic needle tip is withdrawnthrough the annulus.
 21. The system as in claim 15, further comprisingan outer needle to penetrate a skin of the patient, the outer needlecomprising a lumen, the needle sized to fit inside the lumen of outerneedle,
 22. The system as in claim 15, wherein the catheter comprises abend radius from about 5 to 15 mm.
 23. The system as in claim 22,wherein the side port is adapted to pass the catheter with the bendradius from about 5 to 15 mm so as to slide the catheter through theside port while the needle is retracted through the annulus.
 24. Thesystem as in claim 15, wherein the atraumatic needle tip comprises aSpecial Sprotte needle tip.
 25. The system as in claim 15, wherein theneedle comprises an outside diameter no more than about 0.92 mm.
 26. Thesystem as in claim 15, wherein the catheter comprises a balloon anchorsized to pass through the side port.
 27. The system as in claim 15,further comprising: an adapter that connects to a lumen of the catheter;and a wing nut to tighten the adapter on the catheter lumen, wherein thewing nut comprises a slot sized to pass the lumen when the wing nut isremoved from the adapter.
 28. A method of positioning a catheter in anintervertebral disc of a patient, the intervertebral disc having anannulus and a nucleus, the method comprising: advancing a needle topenetrate through a surface of the intervertebral disc into the interiorof the disc, and advancing a catheter through a lumen of the needle intothe interior of the disc.
 29. The method of claim 28, further comprisinginflating a balloon to anchor the catheter in the disc.
 30. A system forpositioning a catheter in an interior of an intervertebral disc, saidsystem comprising: a first needle capable of receiving a first removablestylet for establishing a percutaneous path through a skin towards theintervertebral disc in a patient's body; a second needle capable ofreceiving a second removable stylet, wherein the second needle is sizedto be advanced through a lumen of the first needle, after the firstremovable stylet has been removed, wherein the second needle can beadvanced into the interior of the intervertebral disc; and a cathetersized to be introduced through a lumen of the second needle after thesecond stylet has been withdrawn.
 31. A system as in claim 30, whereinthe first needle includes a removable stylet, obturator or trocar toinhibit coring.
 32. A system as in claim 31, wherein the first needlehas an inner diameter of no more than 1.7 mm and a length in the rangefrom 3 cm to 20 cm.
 33. A system as in claim 30, wherein the secondneedle includes a removable stylet or obturator to inhibit coring.
 34. Asystem as in claim 33, wherein the second needle has an outer diameterno greater than 1.5 mm and an inner diameter of at least 0.38 mm and alength in a range from 10 cm to 30 cm.
 35. A system as in claim 30,wherein the catheter has an outside cross sectional size no greater than1.5 mm and a length in the range from 30 cm to 62 cm.
 36. A system as inclaim 30, wherein the catheter comprises indicia over a proximal portionthereof, wherein the indicia indicate the position of the distal end ofthe catheter relative to the distal end of the second needle.
 37. Asystem as in claim 36, wherein the indicia comprise a scale formedprinted or etched on a surface of the catheter.
 38. A system as in claim36, wherein the indicia comprise a color change on the catheter.
 39. Asystem as in claim 30, wherein the second needle comprises an atraumaticneedle adapted to minimize tissue damage with at least one of anatraumatic tip or a side port.
 40. A system as in claim 39, wherein thesecond needle comprises a ramp near the side port to pass the catheterthrough the side port at a deflection angle of about 5 to 35 degreesfrom the second needle.
 41. A system as in claim 39, wherein the secondneedle comprises a Sprotte needle.
 42. A system as in claim 30, whereinthe second needle comprises a side port and the side port is capable ofsliding along the catheter such that the catheter remains near the discwhen the second needle is retracted.
 43. A system as in claim 30,wherein the second needle comprises a side port and catheter comprisesan expandable balloon sized to pass through the side port.
 44. A systemas in claim 30, wherein at least one of the first needle or the secondneedle comprises tungsten, rhenium, molybdenum, tantalum, palladium,cobalt-chronium, tungsten-rhenium, tungsten-carbide ormolybdenum-rhenium.